Counterweight mounting mechanism



March 26, 1968 E KORENSKY ET Al. 3,375,048

COUNTERWEIGHT MOUNTING MECHANISM 2 Sheets-Sheet 2 Filed NOV. 2l,v 1966 /NVENTORS EDW/N KARENSKY JOSEPH B. T/fFF/N ATTY United States Patent O 3,375,048 COUNTERWEIGHT MOUNTING MECHANISM Edwin Korensky and Joseph B. Tiln, Cedar Rapids,

Iowa, assignors to Link-Belt Company, acorporation of Illinois Filed Nov. 21, 1966, Ser. No. 595,806 `10 Claims. (Cl. 212-49) ABSTRACT F THE DISCLOSURE A construction machine having an under carriage with a platform rotatably mounted thereon, a boom `pivotally associated with one end portion of the platform and ra counterweight removably secured to'the otherpend vportion of the platform by means of a counterweight securing mechanism. The counterweight securing mechanism includes a linkage having a portion for operatively engaging and raising the counterweight and a hydraulic cylinder or other suitable power means for driw'ng the linkage.

This invention relates generally to new -and useful improvements in cranes, shovels, trench hoes, and the like, and more particularly to removable counterweighlts for such machines.

Machines of the type which are employed to lift, maneuver, and handle heavy loads on one side of the machine are normally designed -to operate without -creating excessive bending moments on the structural elements or upsetting the stability of the machine. This is -usually accomplished by supplying 1a counterweight which is attached to the machine :at the .end opposite that to which the load is to be applied so that the forces created by the load will be substantially counterbalanced bythe additional weight of the counterweight.

Construction machines of this type are designed to be transported over the highways from one location to another, :and it is therefore necessary to have the concentrated weight load on the transporting vehicle within the legal weight limitations placed on the highways. Due to the heavy weight of the counterweight required to balance the loading conditions, the counterweight supplied on the machine is usually mounted in amanner to permit its being removed 'from the machine and transported between the different construction sites bymeans of a separate vehicle, thus signicantly aiding in reducing .the weight of the machine to that permitted on the highways. It is therefore desirable to 4have a counterweight adapted to be quickly and easily disconnected from the machine, separately transported to a new locality, and then readily connected to the machine with the least amount of time and labor.

Cranes, shovels, Aand similar type machines have va mobile undercarriage supporting a'platform thereon for rotation in a Vhorizontal plane. A boom assembly is pivotly connected to one end of the platform with the associated power means and operators cab being Ycarried by the platform. To increase the load handling ycapacity of the machine and the effective radius of operation of the boom, a counterweight `is mounted on Athe end of'the platform opposite the end to which the boom assembly is connected. It is apparent that when no load is being Iapplied to the boom, the counterweight applies an unbalanced force to the rotating connection between the platform and the undercarriage thereby creating undesirable bending moments and stresses on this connection. It Would therefore be desirable to have a counterweight which would be detachably connected to the platform so that it could be easily detached therefrom and rested fon the ICC undercarriage when the additional balancing force of the counterweight was not required, and which could Vbe quickly re-attached to the platform when required.

It .is therefore a primary object of this invention to provide .a lnew .and improved counterweight mounting mechanism for quickly and easily attaching and detaching a counterweight to a crane, shovel or similar type machine.

Another object of this invention is to provide a counterweight mounting Amechanism :adapted to Araise the counterweight from an undercarriage to a platform mounted thereon and automatically positively `secure 4it thereto, and which can also readily lower the counterweight from the platformto the undercarria-fge.

A further object of this invention is to provide ya counterweight mounting .mechanism adapted to permit the counterweight to be readily replaced by a counterweight of a different weight.

Still another object of this invention is to provide an apparatus for detachably mounting a counterweight on a machine in a manner which eliminates the need -or manually operated locking devices.

These and other objects and advantages of the invention will be apparent during the course of the following description.

-In the accompanying drawings forming a part of this specification and in which like reference characters are employed lto designate like parts throughout the same;

FIGURE l is a side elevational view of a truck crane incorporating the invention;

FIGURE 2 is an enlarged fragmentary side elevational view with the counterweight shown in sections on avertical, longitudinal ,plane extending through the center line of one of the pair of counterweight mounting vmechanisms and illustrating the inoperative ,position with the counterweight rested on the truck frame;

FIGURE 3 illustrates the counterweight mounting mechanism of FIG. 2 with the counterweight supported in the maximum elevated position on the platform; and

FIGURE 4 illustrates the counterweight mounting mechanism of FIG. 2 with the counterweight positively secured in the operative position on the platform.

In the drawings, wherein for the purpose of illustra-` tion is shown a preferred embodiment of the linvention, and first particularly .referring to FIG. .1, `there is Aillustrated, by way of example, a truck crane 7 consisting of .a crane upper l8 rotatably supported on a ring gear 9 which is mounted on a longitudinally extending vtruck frame 10, the `truck frame in turn being supported -on a plurality of spaced wheels 11. Some of the wheels 11 are drlvingly connected in a conventional .manner :to a drive mechanism, not shown, located in a ydrivers cab 12 mounted on the front end portion of the truck frame 10. The crane upper 8 is a self contained mechanism consisting lof an operators cab 13 Vixedly mounted on a platform 14 having a boom 115 pivot-ally connected to one end thereof. A crane drive mechanism, not shown, vis located in the 'operators cab 13 to provide the power for operating 'the boom 15 and for rotating the crane. upper 8 on the ring gear 9. The platform 14 .includes a pair of laterally spaced parallel side frame members 16 which extend lengthwise along opposite sides of the platform, and a counterweight 17 which is detachably mounted to the rear portion ofthe side A*frame members for balancing the forces and `associ-ated bending moments created by the loads placed on the boom `15. l

Referring now to FIG. 2, there is shown one rof ythe pair of .counterweight mountingmechanisms 18 Amounted on the associatedside 'frame member 16, it being understood that the vother counterwight mounting mechanismv is mounted on the other side frame member and is identical in construction to the counterweight mounting mechanism shown and described hereinafter. The counterweight 17 consists of a casting having a horizontally extending bottom portion 19 and a vertically extending arcuately shaped rear portion 21, the inner surface of which has its center of curvature at the center of rotation of the crane upper 8 and which includes a shoulder-like inwardly projecting annular ange 22.

An integrally formed recessed lug 26 is provided in the ange 22, and a bushing 27 having an external collar 28 welded onto its lower end is secured into an associated cylindrical mounting hole 29 formed in the lug 26. The bushing 27 has an axially drilled threaded bore 31 yfor threadingly receiving a stud 32 having a threaded portion 33 intermediate its end portions. The upper end portion of the stud 32 has a hexagonally shaped head 34 formed thereon while the lower end portion is terminated in a member 35 having a conical recess 36 formed in the bottom surface thereof.

The stud 32 is adjustably threaded into the bore 31 until the bottom surface of the member 35 is a selected distance above the interior surface of the bottom portion 19 of the counterweight 17. This feature of adjustability allows far variations encountered during the casting of the counterweight 17, and also permits additional adjustments to be made at a later date for custom tting the counterweight to a particular machine. After the stud 32 is properly adjusted, a locking plate 37 having a hexagonally shaped aperture formed therein is positioned over the stud head 34 such that the aperture closely sur rounds the stud head to form a fitted relationship therewith. The locking plate 37 rests on the top surface of the recessed lug 26 and the bushing 27 by a set of cap screws 38, thus preventing the rotation of the stud 32 While simultaneously securing the bushing 27 in the mounting hole 29.

Spaced below the lug 26 is an L-shaped recess formed of a horizontally extending leg 39 in the interior surface of the bottom portion 19 and a vertically extending leg 41 in the interior surface of the rear portion 21. An annular member 42 having frusto conical recess 44 is axially aligned with the stud 32 and is then welded in the leg 39. A complementary shaped conical boss 45 is secured to the bottom surface of the back end portion of the Vside framek member 16 and projects downwardly therefrom so as to operatively engage the associated frusto conical recess 44 when the counterweight 17 is raised to the platform 14.

A conical recess 46 is formed in the exterior surface of the bottom portion 19 of the counterweight 17` for use in conjunction with a complementary shaped boss 47 which is secured to the truck frame and projects upwardly therefrom -for positioning and supporting the counterweight thereon. Additional support for the counterweight 17 is provided by a bolt 48 which is adjustably threaded into an apertured plate 49 located a longitudinally spaced distance from the boss 47 and secured to the truck frame 10. The bolt 48 is vertically adjusted to a position at which the counterweight 17 will be supported on a level plane on the truck frame 10, and a nut 51 threaded thereon is then adjusted to tightly abut against the plate 49 to lock the bolt in the adjusted position- A recess 52 is supplied in the truck frame 10 beneath the bolt 48 so as to allow for the vertical adjustment of the bolt relative to the truck frame.

The counterweight mounting mechanism 18 includes a pair of transversely spaced opposed supporting side members 55v and 56 which are interconnected by a front member 57 'and a back member 58, the aforementioned members being suitably mounted on the back end portion of the associated side frame member 16. It will be understood that there is an identically constructed counterweight mounting mechanism 18 associated with each of the lugs 26 on the counterweight 17, and since the two counterweight mounting mechanisms are identically constructed and operate together as a unit, only one of the mechanims and its associated components is illustrated and described hereinafter.

A pair of transversely spaced bearing lblocks 59 are adjustably supported for horizontal movement along a pair of transversely spaced longitudinally extending parallel horizontal members 61 which are welded to the opposed interior surfaces of the side members 55 and 56 respectively. To prevent vertical movement of the bearing blocks 59, a pla-te 62 is positioned over the bearing blocks and is fixedly secured to the side members 55 and 56 by cap screws 63 which are threaded into associated longitudinally extending projections 64 (FIG. 3) secured to the exterior surface of each of the side members. A pair of transversely spaced vertically extending front plates 65 and a pair of transversely spaced vertically extending back plates 66 are welded to the inside surfaces of each of the side members 55 and 56 in a manner to define the horizontal adjustment limits of the bearing blocks S9, and shim plates 67 supplied in varying thicknesses are inserted between the bearing blocks and the front and back plates for positively positioning the bearing blocks. A pair of transversely spaced bolts 68 are then adjustably threaded into corresponding aligned apertures 69 in the front member 57 and front plate 65 to engage a portion olf the shim plates 67 and secure them in position, and a nut 71 supplied on each bolt 68 is then tightened against the front member to lock the bolt in the adjusted position.

One end of an L-shaped member 72 is pivotly connected to the bearing blocks 59 by a pin 73 extending therebetween, and the other end is'terminated in a conically formed head portion 74 adapted to engage the corresponding recess 36 in the member 35. A pair of toggle links 75 and 76 have their adjacent ends pivotly connected together by a pin 77, the upper end of the top link 75 bein-g pivotly connected to the member 72 by a pin 78, and the lower end Iof the bottom link 76 being pivotly connected between the side members 55 and 56 by a pin 79 extending therebetween. The power for operating the counterweight mounting mechanism 18 is supplied by a double acting hydraulic motor 82 having a cylinder portion 83 and a reciprocating piston rod 84 for telescopic reciprocal movement with respect thereto. The base end of the cylinder portion 83 is pivotly connected to a bracket 85 mounted on the side frame member 16 and the outer end of the piston rod 84 is pivotly connected by the pin 77 to the toggle links 75 and 76. Conventional hydraulic` apparatus, not shown, is provided to control and furnish pressurized fluid to the hydraulic motor 82 through suitable uid transmission lines 86 and 87, the associated control valves being preferably located in the operators cab 13 for ease of operation.

The operation is as follows: 'I'he truck crane 7 lifts the counterweight 17 from its transporting vehicle, not shown, and rests it on the truck frame 10 with the bosses 47 engaging their corresponding recess 46 and the bottom portion 19 resting on the bolts 48. As illustrated by FIG. 2, the crane 8 is horizontally rotated onthe ring gear 9 so that the bosses 45 and the head portions 74 of the members 72 are in a position to operatively engage their associated recesses 44 and 36 respectively. To raise the counterweight 17 to the platform 14, the crane operator energizes the hydraulic apparatus to rforce uicl through the uid transmission lines 86 thereby effecting the uniform and simultaneous outward movement of each of the piston rods 84 from their respective cylinder portions 83. It will be understood, of course, that thepair of hydraulic motors 82 are connected in parallel so as to achieve an equal and simultaneous movement of both of the piston rods 84 relative to their associated cylinder portions 83.

The outward movement of the piston rods 84 urges the associated pairs of toggle links 75 and 76 into vertical alignment with one another causing the movement of the pins 78 in an upwardly direction. This iu turn causes the members 72 to pivot about the pins 73 in a direction to eiect the engagement of the head portions 74 with their associated recesses 36 so as to lift the counterweight 17 olf of the truck frame and raise it to the platform 14.

In FIG. 3 the counterweight 17 is shown supported in the maximum raised position with the toggle links 75 and 76 in vertical alignment with each other. This position clamps the counterweight 17 to the platform 14 with the bosses 45 and head'portions 74 engaging their associated recesses 44 and 36 respectively. It is apparent that while the toggle links 75 and 76 are maintained in a vertically aligned position, the counterweight 17. will remain attached to the platform 14. However, should the hydraulic fluid be inadvertently released from the cylinder portions 83, the weight of the counterweight 17 could force the toggle links 75 and 76 out of alignment thus causing the piston rods 84 to lwithdraw Ainto their respective cylinder portions thus unclamping the counterweight from the platform 14. This possibility of accidentally releasing the counterweight 17 from the platform 14 presents a hazard to the personnel working nearby, and for safety reasons it is desirable to provide a means for preventing this from occurring. This is accomplished by having the piston rods 84 drive the joints between each set of toggle links 75 and 76 into an over-center position as illustrated in FIG. 4. Studs 88 are adjustably threaded in apertures 89 in each of the back members 58 to engage the joints between the pairs of toggle links 75 and 76 after the pin 77 has been driven the selected distance over-center, the studs 88 being locked in position by nuts 91 threaded thereon and tightened to abut against the back members. This over-center position of the toggle links 75 and 76 positively secures the counterweight 18 to the platform 14 and prevents the counterweight 17 from accidentally becoming detached therefrom since it is now required that the hydraulic motors 82 rst Ibe energized to pull the toggle links back over-center before the counterweight cwill be released from the platform. This provides an important safety feature of the invention since it is apparent that no power is required to maintain the counterweight 17 locked to the platform 14.

To remove the counterweight 17 lfrom the platform 14 and lower it to the truck frame 10, the crane upper 8 is rotated on the ring gear 9 until the counterweight is properly positioned above the supporting bosses 47 and bolts 48. The crane operator then energizes the hydraulic apparatus to force the iiuid through the fluid transmission line 87 so as to retract the piston rods 84 into their respective cylinder portions 83, and simultaneously releases the hydraulic Huid from the lines 86 which was -previously entrapped in the cylinder portions when the counterweight 17 was attached to the platform 14. This etfects the lowering of the counterweight 17 to the truck frame 10 where it may remain until needed or it can be removed and placed on a separate transporting vehicle to be taken to a new location.

It is to be understood that the lform of this invention herewith shown and described is to be taken as a preferred example of the same, and that various chan-ges in shape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, We claim:

1. In combination with a machine having an undercarriage, platform mounted thereon for rotation in a horizontal plane, a counterweight to be removably secured to one end portion of the platform, a boom operatively associated with the other end portion of the platform and drive means for controlling movement of the boom, the improvement which comprises:

means fory removably Vsecuring the counterweight to said one end portion of the platform; and A powered means independent of said drive means mounted on said -one end portion adjacent to said securing means and operatively associated therewith for raising the counterweight to the platform and automatically positively locking the securing means in the counterweight securing position. 2. The combination delined in claim 1 further characterized by the securing means comprising:

a lever pivotally connected to the platform and operatively associated With the powered means for movement thereby to cause pivotal movement of the lever in a substantially vertical plane and to cause a portion of the lever to engage and secure the counterweight to the platform.

3. The combination defined in claim 1 wherein the securing means comprises:

a linkage including a. plurality of elements, one of the elements being pivotally connected to the platform and a second of said elements being operatively associated with the powered means for moving the one element in a substantially vertical plane to secure the counterweight to the platform.

4. The combination defined in claim 1 wherein the securing means comprises:

a lever pivotally connected to the platform and having a counterweight engaging portion which is moveable in a substantially vertical plane; and

a toggle linkage operatively associated with the lever and with the powered means, a portion of the toggle linkage being pivotally connected to the platform so that energization of the powered means will urge the toggle linkage into a straightened position to effect the operative engagement of the counterweight engaging portion yof the lever with the counterweight so as to raise it to the platform and secure it thereto.

5. The combination dened in claim 2 wherein the lever is pivotally connected 'to the platform by a bearing means adjustably supported on the platform so as to permit adjustable movement of the lever to align the counterweight engaging portion of the lever with the counterweight.

6. The combination defined in claim 2 further characterized by the counterweight engaging portion of the lever engaging a stud vertically adjustably secured to the counterweight in a manner which will permit adjustment of the stud to a position at which the counterweight will be properly secured to the platform.

7. The combination defined in claim 4 further characterized by the powered means urging the toggle linkage beyond its straightened position; and an abutment engaging said toggle linkage to support the latter in its over-center position and to cause the lweight of the counterweight to lock the lever and toggle linkage in the counterweight securing position.

8. The combination defined in claim 7 further characterized by the powered means being operable in one directron to raise and secure the counterweight to the platform, and operable in an opposite direction to detach the counterweight from the platfrom and lower it therefrom to a position separated from the platform.

. 9. In combination with a machine having an undercarriage and a counterweighted platform mounted thereon for rotation in a horizontal plane, the improvement which comprises:

a pair of levers each being pivotally connected to the platform and having a counterweight engaging portion thereon free for movement in a substantially vertical plane for operatively engaging the counter- 'weigh-t;

a toggle linkage operatively associated with each lever,

each toggle linkage having one end pivotally connected to the platform and the other end connected to the associated lever for imparting movement toggle linkage, the motor means being in fluid comfthereto; f munication with the source such that energization of means for limiting the movement of the toggle linkage; the motor means will cause the movement of the and toggle linkages in a manner to effect the operative powered means operatively associated with each of the 5 positioning `of the counterweight on the platform.

toggle linkages for urging them beyond a straightened position so as to cause the engagement of the counter- References Cited weight engaging portion of each lever with the coun- UNITED STATES PATENTS -terweight and etect the raising thereof to the plati 3,251,479 5/1966 Lonngren 212--49 form and automatically positively lock 1t thereto. 10 1278,04 5 10/1966 Poner 212 49 10. The combination defined in claim 9 further characterized by the powered means comprising: RICHARD E AEGERTER Primary Examiner a source of pressure iiuid; and

reciprocal pressure uid operated motor means mounted EVON C- BLUNK, Examineron the platform and operatively connected to each H C. HORNSBY, Assistant Exam-nen 

